|RATCLIFF, M - University Of Arkansas|
|KEGLEY, E - University Of Arkansas|
|POWELL, J - University Of Arkansas|
|HAWLEY, J - University Of Arkansas|
|LUSBY, K - University Of Arkansas|
|ROWE, M - University Of Arkansas|
|DANIELS, L - University Of Arkansas|
|HUBBELL, D - University Of Arkansas|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2014
Publication Date: 7/1/2014
Citation: Ratcliff, M.D., Kegley, E.B., Powell, J.G., Hawley, J., Lusby, K.S., Rowe, M.P., Gunter, S.A., Daniels, L.B., Hubbell, D.S. 2014. Assessment of the effect of castration upon arrival on long-term growth performance of stocker cattle. Professional Animal Scientist. 30:466-475.
Interpretive Summary: After purchasing new cattle for growing on pasture, managing them in a way that reduces morbidity and maximizes weight gain is economically beneficial to the owner. Furthers, cattle that have been treated for bovine respiratory disease more than two times have been shown to yield inferior carcasses and return less to the cattle feeding enterprise. One issue facing the manager of these cattle is whether it is better to pay the premium and purchase steers, or take advantage of the discount and purchase bull to be castrated after arrival at the ranch. To help answer this question, records were used to quantify the impact of castration and dehorning of calves on average daily gain over receiving and through grazing. Male calves (1,105 claves; BW = 409 ± 52 lb) received over a three-years period were used to assess the effects of castration and dehorning on receiving health and average daily gain, as well as subsequent grazing performance. All bulls (672 calves) were castrated upon arrival, and their average daily gain and morbidity over the course of the receiving (22 to 69 days) and grazing (44 to 217 days) periods were compared to calves received as steers (433 calves). During the receiving period, bulls gained (1.17 lb/d) less than steers (1.43 lb/d); also, polled calves gained (1.37 lb/d) more than dehorned calves (1.17 lb/d). However, during the grazing period there were no differences in average daily gain between castrated bulls and steers, or polled and dehorned calves. This study suggests that when purchasing bulls over steers or horned calves over polled calves due to lower initial costs, care must be given to assure that the discount pays for the reduced performance, but these effects do not carryover in to the grazing period.
Technical Abstract: Existing records were used to quantify the impact of castration and dehorning of calves upon arrival at a stocker unit on long-term growth performance and morbidity. Male calves (n = 1,105; BW = 186 ± 24 kg) received over a three-year period were used to assess the effects of castration and dehorning on receiving health and average daily gain, as well as subsequent grazing performance. Data were compiled from nine studies in which the protocols used were similar. All bulls (n = 672) were castrated upon arrival, and their average daily gain and morbidity over the course of the receiving (22 to 69 days) and grazing (44 to 217 days) periods were compared to calves received as steers (n = 433). During the receiving period, bulls gained 0.12 kg/d less than steers (P < 0.01), and polled calves gained 0.09 kg/d more than dehorned calves (P < 0.01). During the grazing period there were no differences (P = 0.39) in average daily gain between castrated bulls and steers, or polled and dehorned calves. For the combined receiving and grazing periods, steers tended (P = 0.09) to gain body weight faster (0.67 kg/d) than castrated bulls (0.62 kg/d), and polled calves tended (P = 0.11) to have higher average daily gain (0.65 kg) than dehorned calves (0.61 kg). This study suggests that purchasing bulls over steers, or horned calves over polled calves due to lower initial costs, would have a negative impact on receiving average daily gain and the overall average daily gain, but would not affect performance during the grazing period.